Beam recovery procedure using a second component carrier

ABSTRACT

Systems, methods, and apparatuses for performing a beam recovery procedure using a second CC are disclosed. A UE may perform a beam recovery procedure using two component carriers (CCs): for example, CC1 may be a beam formed millimeter wave (MMW) carrier having a beam recovery procedure and CC2 may be an assisting carrier such as a sub-6 GHz carrier. In a first example, a UE may trigger beam recovery for CC1 (on CC2), generate a beam measurement report, and transmit the beam report on resources allocated for uplink transmission on CC2. In a second example, a new scheduling request (SR) may be defined on CC1 for CC2 beam recovery. In a third example, RACH resources or procedures on CC2 may be used to perform the beam recovery for CC1.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims benefit of U.S. Provisional Application Ser. No.62/556,917, entitled “BEAM RECOVERY PROCEDURE USING A SECOND COMPONENTCARRIER” and filed Sep. 11, 2017, which is expressly incorporated byreference herein in its entirety.

BACKGROUND

Aspects of the present disclosure relate generally to wirelesscommunication networks, and more particularly, to performing a beamrecovery procedure for a first component carrier (CC) using a secondcomponent carrier.

Wireless communication networks are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems, orthogonalfrequency-division multiple access (OFDMA) systems, and single-carrierfrequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. For example, a fifth generation (5G)wireless communications technology (which can be referred to as newradio (NR)) is envisaged to expand and support diverse usage scenariosand applications with respect to current mobile network generations. Inan aspect, 5G communications technology can include: enhanced mobilebroadband addressing human-centric use cases for access to multimediacontent, services and data; ultra-reliable-low latency communications(URLLC) with certain specifications for latency and reliability; andmassive machine type communications, which can allow a very large numberof connected devices and transmission of a relatively low volume ofnon-delay-sensitive information. As the demand for mobile broadbandaccess continues to increase, however, further improvements in NRcommunications technology and beyond may be desired.

For example, for NR communications technology and beyond, current beamrecovery solutions may not take advantage of the availability ofmultiple CCs in different frequency bands. That is, a wireless device(e.g., a device operating in millimeter wave (MMW) spectrum) may usedirectional transmissions to increase signal strength. In some cases,the beam direction of the directional transmission may change. If thebeam is not changed, the communication signal may be compromised orlost. Thus, improvements in beam recovery operations may be desired.

SUMMARY

A user equipment (UE) may be configured with multiple component carriers(CCs). For example, CC1 may be a beam formed millimeter wave (MMW)carrier having a beam recovery procedure and CC2 may be an assistingcarrier such as a sub-6 GHz carrier. If the UE detects a condition forperforming a beam recovery procedure on CC1, it may transmit a signal toa serving base station using CC2. For example, the UE may transmit abeam recovery scheduling request (BR-SR) signal (alternatively referredto as beam recovery signal or a scheduling request) using a scheduleduplink resource on CC2, scheduling request resource, PUCCH resource, ora random access channel (RACH) resource in order to perform beamrecovery for CC1.

In one embodiment, a method may include a base station establishingcommunication with a UE over a first component carrier using one or morebeams, receiving a BR-SR from the UE over a second component carrier inresponse to the UE initiating beam recovery, identifying a candidatebeam on the first component carrier based on the BR-SR received on thesecond component carrier, and communicating with the UE over the firstcomponent carrier using the candidate beam.

In one embodiment, a non-transitory computer-readable medium may includeinstructions operable to cause a processor to establish communicationwith a UE over a first component carrier using one or more beams,receive a BR-SR from the UE over a second component carrier in responseto the UE initiating beam recovery, identify a candidate beam on thefirst component carrier based on the BR-SR received on the secondcomponent carrier, and communicate with the UE over the first componentcarrier using the candidate beam.

In one embodiment, an apparatus may include a processor, memory inelectronic communication with the processor, and instructions stored inthe memory. The instructions may be operable to cause the processor toestablish communication with a UE over a first component carrier usingone or more beams, receive a BR-SR from the UE over a second componentcarrier in response to the UE initiating beam recovery, identify acandidate beam on the first component carrier based on the BR-SRreceived on the second component carrier, and communicate with the UEover the first component carrier using the candidate beam.

In one embodiment, an apparatus may include means for establishingcommunication with a UE over a first component carrier using one or morebeams, means for receiving a BR-SR from the UE over a second componentcarrier in response to the UE initiating beam recovery, means foridentifying a candidate beam on the first component carrier based on theBR-SR received on the second component carrier, and means forcommunicating with the UE over the first component carrier using thecandidate beam.

In another embodiment, a method may include communicating with a basestation over a first component carrier using one or more beams,determining to trigger beam recovery for the first component carrier,identifying a candidate beam for communication with the base stationbased on the determining, and transmitting a BR-SR from the UE to thebase station over a second component carrier to signal beam recovery forthe first component carrier.

In one embodiment, a non-transitory computer-readable medium may includeinstructions operable to cause a processor to communicate with a basestation over a first component carrier using one or more beams,determine to trigger beam recovery for the first component carrier,identify a candidate beam for communication with the base station basedon the determining, and transmit a BR-SR from the UE to the base stationover a second component carrier to signal beam recovery for the firstcomponent carrier.

In one embodiment, an apparatus may include a processor, memory inelectronic communication with the processor, and instructions stored inthe memory. The instructions may be operable to cause the processor tocommunicate with a base station over a first component carrier using oneor more beams, determine to trigger beam recovery for the firstcomponent carrier, identify a candidate beam for communication with thebase station based on the determining, and transmit a BR-SR from the UEto the base station over a second component carrier to signal beamrecovery for the first component carrier.

In one embodiment, an apparatus may include means for communicating witha base station over a first component carrier using one or more beams,means for determining to trigger beam recovery for the first componentcarrier, means for identifying a candidate beam for communication withthe base station based on the determining, and means for transmitting aBR-SR from the UE to the base station over a second component carrier tosignal beam recovery for the first component carrier.

Moreover, the present disclosure also includes apparatus havingcomponents or configured to execute or means for executing theabove-described methods, and computer-readable medium storing one ormore codes executable by a processor to perform the above-describedmethods.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects of the present disclosure will hereinafter bedescribed in conjunction with the appended drawings, provided toillustrate and not to limit the disclosed aspects, wherein likedesignations denote like elements, where a dashed line may indicate anoptional component, and in which:

FIG. 1 shows a wireless communication network that supports performing abeam recovery procedure using a second component carrier (CC) inaccordance with aspects of the present disclosure.

FIG. 2 shows a spectrum diagram that illustrates aspects of thefrequency range in which some of the communications described herein areperformed in accordance with aspects of the present disclosure.

FIG. 3 shows a schematic diagram that supports performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure.

FIG. 4 shows a beam recovery configuration that supports performing abeam recovery procedure using a second CC in accordance with aspects ofthe present disclosure.

FIGS. 5 and 6 show schematic diagrams that support performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure.

FIGS. 7 through 17 show flowcharts that support performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that such aspect(s) maybe practiced without these specific details. Additionally, the term“component” as used herein may be one of the parts that make up asystem, may be hardware, firmware, and/or software stored on acomputer-readable medium, and may be divided into other components.

Beamforming is a technique for directional signal transmission andreception that may be used, for example, for transmission in themillimeter wave (MMW) band. The use of beamforming may depend on factorssuch as the type of signal being transmitted and the channel conditions.If the beam direction is lost or degraded, a beam recovery procedure maybe performed in which a user equipment (UE) sends a beam recoveryscheduling request (BR-SR) with a good reference beam. A base stationreceiving a beam on this resource infers the identity of the transmittedreference beam. Therefore, by detecting a BR-SR signal, the base stationmay learn that the UE is requesting a beam recovery, and may also learnan identity of the good beam selected by the UE. However, if this BR-SRsignal is communicated in another carrier, e.g., a sub-6 GHz carrier,this implicit beam identity information may not be communicated to thebase station.

Aspects of the present disclosure solve the above-identified problem byimplementing techniques to conduct a beam recovery for a first carrier(e.g., a MMW carrier) using signals transmitted in second carrier (e.g.,a sub-6 GHz carrier or a MMW carrier in a different band than that ofthe first carrier). The second carrier (e.g., a sub-6 GHz carrier), insome examples, may assist the base station in acquiring measurementreports and implementing beam switch procedure for the first carrier(e.g., a mmW carrier). In some examples, it should be appreciated thatthe second carrier (e.g., assisting cell) may not necessary have thesame carrier frequency for downlink communication and uplinkcommunications. By way of an example, a UE may be configured with twoCCs: CC1 may be a beam formed MMW carrier having a beam recoveryprocedure and CC2 may be an assisting carrier such as a sub-6 GHzcarrier. When UE detects a need for initiating beam recovery (e.g., bymeasuring reference beams in SS or CSI-RS beam sweep and determiningthat the current active beam signal quality has fallen below athreshold, or alternatively by detecting a separate candidate beam thathas emerged that offers improved signal quality than the signal qualityoffered by the current active beam), the UE may trigger beam recovery onCC2 by transmitting a BR-SR signal to the base station. In someexamples, the BR-SR signal may be similar to a regular SR signal andCDMed (Code Division Multiplexed), FDMed (Frequency DivisionMultiplexed) or TDMed (Time Division Multiplexed) with regular SR orwith PRACH. E.g., BR-SR signal may be based on a different sequence thanthat of the regular SR or the PRACH. In these examples, BR-SR may serveas a logical beam trigger signal (e.g., 1 bit) that signals to the basestation that a beam recovery has been triggered by the UE. Aspects ofthe present disclosure provide multiple techniques that implement theabove techniques. It should be appreciated by those of ordinary skillthat any features of the specific techniques described below may beinterchangeable and is not limited to the example, as described.

In a first example, a UE may trigger beam recovery for CC1 on CC2 bygenerating a beam measurement report and transmitting the beammeasurement report on resources allocated for UL transmission on CC2.The beam measurement report may be generated by MAC layer andmultiplexed with UL data on PUSCH of the CC2 as a MAC-CE. However, if noPUSCH resources are allocated on CC2, the UE may trigger a regular SR onCC2 on resources allocated for regular SR. In some cases, e.g., when UEis not UL synchronized, and if no PUSCH resources are allocated on CC2,the UE may trigger a RACH procedure on CC2. In some aspects, the beammeasurement report may comprise one or more beam identifications (IDs).The beam IDs may identify an emerging candidate beam and an ID of acurrent active beam. Report may further comprise beam strengthmeasurements for one or more of these beams, e.g., RSRP or CQI of thebeams. In some examples, a MAC entity at the UE may have multiple mmWcells (instead of just one, namely, CC1 in above example.) Many of thesecells may detect beam failure and trigger a beam measurement report atthe same time. In such instance, only one report may be transmitted bythe UE. In some examples, the BS may configure cell groups for beamreporting (e.g., group cells based on beam-coherence). For example, thebase station may configure a separate BR-SR for each cell group.Additionally or alternative, the base station may configure one SR formultiple cell groups. In such instances, the base station and/or the UEmay implement a “prohibit timer” that may be associated with the BR-SRfor each cell group. The “prohibit timer” may prevent a cell group fromtriggering multiple BR-SRs in a short duration. The “prohibit timer” mayalso prevent superfluous MAC-CEs per cell group. Then UE may transmitone report per cell group and cancel all other reports from cells in thecell group.

In a second example, a new scheduling request may be defined on CC2 forCC1 beam recovery. For example, a BR-SR on CC2 may convey the 1-bitinformation that the UE has triggered beam recovery procedure for CC1.Upon transmitting the BR-SR to the base station, the UE may monitorPDCCH on CC2 for DCIs related to CC1. Specifically, in such instance,the UE may monitor CC2 for DCIs triggering beam measurement reports forCC1. Moreover, the UE may monitor DCIs triggering CSI-RS on CC1 and abeam measurement report based on this CSI-RS. In some examples, the UEmay monitor PDCCH on CC2 over a predetermined time window which maystart after the transmission of BR-SR on CC2. If the UE receives a DCIon CC2 related to CC1, the time window may be extended by apredetermined amount. This extension may be computed from the time theUE received the DCI.

In this example, the base station, in response to receiving the newscheduling request (or logical beam trigger signal), may request the UEto provide a beam measurement report such that the base station mayidentify a candidate beam that provides improved signal quality. Thebase station may also identify from the report the identity of failedbeam(s). In some aspects, the candidate beam may be one of a pluralityof current active beams on which the UE may be communicating with thebase station, or in the alternative the candidate beam may be anotherbeam identified as offering improved signal quality in comparison to theplurality of currently active beams. The UE, upon receiving a triggerand resource for beam measurement report, may transmit beam measurementreport on the allocated resources. The allocated resources may be PUSCHresources or PUCCH resources. For example, for a short beam measurementreport, e.g., comprising one measurement, the resources may be allocatedon PUCCH or PUSCH, whereas for long beam measurement report, e.g.,comprising multiple measurements, the resources may be allocated onPUSCH. The beam measurement report may be transmitted on either CC1 orCC2. The DCI in such instances may indicate which CC (e.g., CC1 or CC2)the UE is requested to transmit the beam measurement report on). The DCImay also command the UE to switch a control beam on CC1 to a beamincluded in the report. This beam may be one of the beam with best RSRP,the first beam in the report, or the beam with best RSRP that isn'talready being used as active beam. The UE and base station may apply thebeam switch at a predetermined time, e.g., with a predetermined time gapafter the transmission of the beam measurement report.

Upon transmitting the beam measurement report to the base station onCC2, the UE may switch PDCCH beam for CC1 to the candidate beamidentified in the beam measurement report. As indicated above, thecandidate beam that the UE may switch to may provide improved signalquality than the currently active beam used for communication betweenthe UE and base station. Additionally or alternatively to the UEcompletely switching the PDCCH beam to the candidate beam, the UE mayswitch the PDCCH beam for a first time period (e.g., subset ofpreconfigured PDCCH search spaces (i.e., OFDM symbols)) and switch backto the current PDCCH beam for the second time period. In such instance,PDCCH monitoring pattern may be implemented in an interleaved manner.

In further alternative, instead of continuously switching the PDCCH beamto the candidate beam preemptively, the UE may also monitor CC2 for abeam switch command for CC1 PDCCH beam to be received from the basestation on the CC2. Even further, the UE may monitor CC1 on the currentPDCCH beam in order to receive the beam switch command on the CC1 beforethe UE switches the PDCCH beam to the candidate beam.

In accordance with the third example, a robust new beam recovery signalis disclosed for transmission on CC2 for conducting beam recovery forCC1 using the CC2. In such example, the BR-SR may explicitly convey thebeam ID of the candidate beam that was being implicitly conveyed in theBR-SR transmitted on CC1. As such, the base station may identify thecandidate beam that offers improved signal quality based on receivingthe BR-SR.

In accordance with the fourth example, features of the presentdisclosure may utilize existing RACH procedure on CC2 for performingbeam recovery on CC1. RACH procedure on CC2 may be contention freerandom access (CFRA) or contention based random access (CBRA).

In the instance of CFRA, a preamble may be assigned to a UE on CC2 forconveying beam recovery signal on CC1. Upon receiving the message ofCFRA on CC2, the base station may identify the UE that wants to conveybeam recovery or scheduling request on CC1. However, because the basestation may not know the exact beam ID that UE wants to convey to BS,the base station may request the UE to generate and transmit a beamrecovery report. Alternatively, in another example, a set of preamblesmay be assigned to a UE on CC2 for conveying beam recovery signal onCC1. Each preamble in the set may be mapped to a different beam on CC1.As such, upon receiving preamble of CFRA on CC2, the base station mayuniquely identify the candidate beam to use for the UE.

In the instance of CBRA, the UE may convey, through a message, that theUE transmitted RACH to base station in order to request beam recovery onCC1. The message may convey a 1 bit signal that identifies UE's reasonto transmit RACH. The message may also contemporaneously convey both thebeam index of CC1 that UE has detected before and plans to utilize toconvey its beam recovery request. Upon receiving the message, the basestation may either automatically switch the identified candidate beam orissue a beam switch command to the UE to switch the PDCCH beam to thecandidate beam.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

FIG. 1 shows a wireless communication network 100 that supportsperforming a beam recovery procedure using a second component carrier(CC) in accordance with aspects of the present disclosure. Wirelesscommunication network 100 may include the following components: basestation 105, access point (AP) 110, user equipment (UE) 115, coveragearea 120, communication link 125, direct wireless link 130, backhaullink 135, and core network 140.

Base stations 105 may incorporate aspects of the base stations describedwith reference to FIGS. 3, 5, and 6. Base stations 105 may interfacewith the core network 140 through backhaul links 135 (e.g., S1, etc.).The base stations 105 may perform radio configuration and scheduling forcommunication with the UEs 115, or may operate under the control of abase station 105 controller (not shown). In various examples, the basestations 105 may communicate, either directly or indirectly (e.g.,through core network), with one another over backhaul links 135 (e.g.,X1, etc.), which may be wired or wireless communication links 125.

Base stations 105 may wirelessly communicate with the UEs 115 via one ormore base station antennas. In some examples, base stations 105 may bereferred to as a base transceiver station, a radio base station 105, anaccess point, an access node, a radio transceiver, a NodeB, evolved nodeB (eNB), gNB, Home NodeB, a Home eNodeB, a relay, or some other suitableterminology. The wireless communication network may include basestations 105 of different types (e.g., macro base stations or small cellbase stations, described below). Additionally, the plurality of basestations 105 may operate according to different ones of a plurality ofcommunication technologies (e.g., 5G (or new radio (NR)), fourthgeneration (4G)/Long Term Evolution (LTE), 3G, Wi-Fi, Bluetooth, etc.),and there may be overlapping geographic coverage areas 120 for differentcommunication technologies.

Base stations 105 may include access communications management component145, which may establish communication with a UE 115 over a firstcomponent carrier using one or more beams and communicate with the UE115 over the first component carrier using the candidate beam asdescribed below. In some examples, access communications managementcomponent 540 may include the following components: BS-SR component 542,beam selection component 544, and RACH component 546. In some cases, thefirst component carrier is a MMW carrier and the second componentcarrier is a sub-6 GHz carrier. These components may perform thefunctions described below with reference to FIG. 5.

UEs 115 may incorporate aspects of the UEs described with reference toFIGS. 3, 5, and 6. A UE 115 may also include or be referred to by thoseskilled in the art as a mobile station, a subscriber station, a mobileunit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology.For example, a UE 115 may be a cellular phone, a smart phone, a personaldigital assistant (PDA), a wireless modem, a wireless communicationdevice, a handheld device, a tablet computer, a laptop computer, acordless phone, a smart watch, a wireless local loop (WLL) station, anentertainment device, a vehicular component, a customer premisesequipment (CPE), or any device capable of communicating in wirelesscommunication network. Additionally, a UE 115 may be internet of things(TOT) or machine-to-machine (M2M) type of device, e.g., a low power, lowdata rate (relative to a wireless phone, for example) type of device,that may in some aspects communicate infrequently with wirelesscommunication network or other UEs 115. A UE 115 may be able tocommunicate with various types of base stations 105 and networkequipment including macro eNBs, small cell eNBs, macro gNBs, small cellgNBs, relay base stations 105, and the like.

UEs 115 may include mobile communications management component 165.Mobile communications management component 165 may communicate with abase station 105 over a first component carrier using one or more beams.In some examples, mobile communications management component 640 mayinclude the following components: beam recovery component 642, beamcandidate component 644, UE BS-SR component 646, monitoring component648, and beam measurement component 650. These components may performthe functions described below with reference to FIG. 6.

Each of the base stations 105 may provide communication coverage for UEs115 over a respective geographic coverage area 120. The geographiccoverage area 120 for a base station 105 may be divided into sectors orcells making up only a portion of the coverage area 120 (not shown). Thegeographic coverage area 120 may represent a macro cell, a small cell,or other types of cell. The term “cell” is a 3GPP term that can be usedto describe a base station 105, a carrier or component carrierassociated with a base station 105, or a coverage area 120 (e.g.,sector, etc.) of a carrier or base station 105, depending on context. Amacro cell may generally cover a relatively large area (e.g., severalkilometers in radius) and may allow unrestricted access by UEs 115 withservice subscriptions with the network provider.

A small cell may include a relative lower transmit-powered base station105, as compared with a macro cell, that may operate in the same ordifferent frequency bands (e.g., licensed, unlicensed, etc.) as macrocells. Small cells may include pico cells, femto cells, and micro cellsaccording to various examples. A pico cell, for example, may cover asmall area and may allow unrestricted access by UEs 115 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessand/or unrestricted access by UEs 115 having an association with thefemto cell (e.g., in the restricted access case, UEs 115 in a closedsubscriber group (CSG) of the base station 105, which may include UEs115 for users in the home, and the like). A base station 105 for a macrocell may be referred to as a macro eNB. A base station 105 for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. A base station 105 may support one or multiple (e.g., two,three, four, and the like) cells (e.g., component carriers).

The core network 140 may include components for management mobilecommunications such as one or more mobility management entity (MME)s,serving gateways, packet gateways, or home subscriber service (HSS)components. In some cases, the core network 140 comprises an evolvedpacket core (EPC). The core network 140 may provide user authentication,access authorization, tracking, internet protocol (IP) connectivity, andother access, routing, or mobility functions.

In some examples, wireless communication network 100 may be or includeone or any combination of communication technologies, including a NR or5G technology, a Long Term Evolution LTE or LTE-Advanced (LTE-A) orMuLTEfire technology, a Wi-Fi technology, a Bluetooth technology, or anyother long or short range wireless communication technology. InLTE/LTE-A/MuLTEfire networks, the term eNB may be generally used todescribe the base stations 105, while the term ‘UE’ may be generallyused to describe the UEs 115. The wireless communication network 100 maybe a heterogeneous technology network in which different types of eNBsprovide coverage for various geographical regions.

The communication networks that may accommodate some of the variousdisclosed examples may be packet-based networks that operate accordingto a layered protocol stack and data in the user plane may be based onthe internet protocol (IP). A user plane protocol stack (e.g., packetdata convergence protocol (PDCP), radio link control (RLC), MAC, etc.),may perform packet segmentation and reassembly to communicate overlogical channels. For example, a MAC layer may perform priority handlingand multiplexing of logical channels into transport channels. The MAClayer may also use hybrid automatic repeat request (HARQ) to provideretransmission at the MAC layer to improve link efficiency. In thecontrol plane, the radio resource control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and the base stations 105. The RRC protocollayer may also be used for core network support of radio bearers for theuser plane data.

At the physical (PHY) layer, the transport channels may be mapped tophysical channels. In some aspects of the wireless communicationnetwork, base stations 105 or UEs 115 may include multiple antennas foremploying antenna diversity schemes to improve communication quality andreliability between base stations 105 and UEs 115. Additionally oralternatively, base stations 105 or UEs 115 may employ multiple input,multiple output (MIMO) techniques that may take advantage of multi-pathenvironments to transmit multiple spatial layers carrying the same ordifferent coded data. Wireless communication network may supportoperation on multiple cells or carriers, a feature which may be referredto as carrier aggregation (CA) or multi-carrier operation. A carrier mayalso be referred to as a CC, a layer, a channel, etc. The terms“carrier,” “component carrier,” “cell,” and “channel” may be usedinterchangeably herein.

A UE 115 may be configured with multiple downlink CCs and one or moreuplink CCs for carrier aggregation. Carrier aggregation may be used withboth frequency division duplexing (FDD) and time division duplexing(TDD) component carriers. The base stations 105 and UEs 115 may usespectrum up to Y MHz (e.g., Y=5, 10, 15, or 20 MHz) bandwidth percarrier allocated in a carrier aggregation of up to a total of Y*x MHz(x=number of component carriers) used for transmission in eachdirection. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to downlink (DL)and UL (e.g., more or less carriers may be allocated for DL than forUL). The component carriers may include a primary component carrier andone or more secondary component carriers. A primary component carriermay be referred to as a primary cell (PCell) and a secondary componentcarrier may be referred to as a secondary cell (SCell).

A beam recovery procedure may include a UE 115 sending a BR-SR signal(alternatively called beam recovery signal or a scheduling request) on aresource associated (i.e. thru spatial quasi co-location (QCL) antennaport indication, with a good reference beam). The reference beam may bepart of a synchronization signal (SS) or channel state informationreference signal (CSI-RS) beam sweep that the UE 115 measures toinitiate beam recovery or to determine a good emerging beam candidate. Abase station 105 receiving one or more beams on this resource isassociated (e.g., QCL) with the transmitted reference one or more beams.Therefore, by detecting a BR-SR signal, the base station 105 may learnthat the UE 115 is requesting a beam recovery as well as an identity ofthe good beam selected by the UE 115.

A may be UE 115 configured with two CCs: CC1 may be a beamformed MMWcarrier having a beam recovery procedure and CC2 may be an assistingcarrier such as a sub-6 GHz carrier. In some cases, a network mayconfigure CC2 as the assisting carrier for CC1, for example the networkmay configure CC2 as a physical uplink control channel (PUCCH) cell forCC1. A UE 115 may detect conditions for initiating beam recovery, forexample, by measuring reference beams in a SS or CSI-RS beam sweep. Theconditions for initiating a beam recovery may also include detectingthat the current beam (e.g., the physical downlink control channel(PDCCH) beam) has weakened or detecting that a candidate beam hasemerged that is significantly better than a currently used beam. Thismay trigger a beam recovery operation on CC2 (since CC2 has beenconfigured by NW for beam recovery of CC1).

In a first example, a UE 115 may trigger beam recovery for CC1 (on CC2),generate a beam measurement report, and transmit the beam report onresources allocated for uplink (UL) transmission on CC2. The beammeasurement report may be generated by a media access control (MAC)layer and multiplexed with UL data on physical uplink shared channel(PUSCH) of the CC2. If no PUSCH resources are allocated on CC2, the UE115 may trigger a scheduling request on CC2. The beam measurement reportmay include one or more beam identifications (IDs), including the beamIDs of emerging candidate beams and an ID of a current active beam. Thereport may further include beam strength measurements for one or more ofthese beams, e.g., received signal reference power (RSRP) or channelquality information (CQI) of the beams. A MAC entity at the UE 115 mayhave multiple MMW cells (i.e., instead of just CC1). In some cases, manyof these cells may detect beam failure and trigger a beam measurementreport at the same time. In this case, the UE 115 may send a singlereport. In some cases, a base station 105 may configure cell groups forbeam reporting (e.g., group cells based on beam-coherence). Then UE 115may transmit one report per cell group and cancel all other reports.

In a second example, a new scheduling request may be defined on CC1 forCC2 beam recovery. For example, a BR-SR on CC2 may convey the 1-bitinformation that the UE 115 has triggered beam recovery procedure forCC2. First, the UE 115 determines to trigger beam recovery for CC1 onCC2, and transmits BR-SR on CC2. In some cases, the expected basestation 105 behavior upon detection of this BR-SR from the UE 115 is totrigger an SS or CSI-RS measurement report for CC.

In a first alternative of the second example, the UE 115 monitors PDCCHon CC2 for downlink control information (DCI)s related to CC1 aftersending a BR-SR. In some cases, if CC2 isn't the scheduling cell forCC1, the UE 115 may not monitor CC2 DCIs triggering beam measurementreports for CC1. The UE 115 may monitor PDCCH on CC2 over apreconfigured time window, starting after the transmission of BR-SR onCC2. Specifically, UE 115 may monitor CC2 for DCIs triggering beammeasurement reports for CC1.

Upon receiving a trigger and resource for beam measurement report, UE115 transmit beam measurement report. This may be transmitted on CC1 orCC2. In some cases, DCI may indicate which CC to transmit this reporton. After transmitting the beam measurement report the UE 115 may eitherUE 115 switch PDCCH to a beam included in the beam measurement report ormonitor CC2 for a beam switch command. If the UE 115 switches the PDCCH,the switch may happen at a preconfigured time after the transmission ofthe beam measurement report. Moreover, the UE 115 may switch PDCCH for asubset of preconfigured PDCCH search spaces (e.g., certain orthogonalfrequency-division multiplexing (OFDM) symbols) but not switch forothers. That is, the UE 115 may continue to use the current PDCCH beamon those other search spaces. PDCCH monitoring pattern may happen in aninterleaved manner.

If the UE 115 has conveyed multiple beam IDs in the beam measurementreport, it may use different RX beam to receive these different beams.In this case, the base station 105 can try different TX beams indifferent subsets of the monitoring period. For example, if a totalmonitoring period is 4T and the UE 115 reports 4 beams, the base station105 will transmit through beam 1 during time 0 to time T, beam 2 duringtime T to 2T and so on. The UE 115 may select its RX beam accordingly. Abase station 105 can convey this pattern a priori to the UE 115 or thisinterleaved pattern can be specified in the spec. If the UE 115 monitorsCC2 (i.e., DCI or MAC CE) for a beam switch command for CC1 PDCCH beam,the monitoring may be limited to a preconfigured time window startingafter the transmission of beam measurement report.

In a second alternative of the second example, the UE 115 continuesmonitoring CC1 on the current beam and expects to receive a trigger andresource for beam measurement report for CC. That is, the UE 115 mayfollow a standard procedure after sending the BR-SR on CC. In thisalternative, CC2 may not temporarily assume responsibility of beamrecovery of CC. That is, if the BR-SR contains no information regardinga new good beam the UE 115 has discovered, there base station 105 andthe UE 115 may wait to perform a beam recovery until after a furtherinformation exchange.

In a third example, a new scheduling request on CC2 may explicitlyconvey a missing beam id that was implicitly conveyed in the BR-SRtransmitted on CC1 itself. In this example, the UE 115 may trigger beamrecovery for CC1 on CC2, and then transmits BR-SR on CC2, where BR-SRcomprises an identity of a good beam selected by the UE 115. Similaralternatives as described in the second example may be applicable forthe third example. That is, the UE 115 may switch PDCCH beam on CC1after sending BR-SR (at least on a subset of search spaces) or CC2 mayexplicitly trigger a beam switch for CC2 to the beam indicated in theBR-SR.

In a fourth example, an existing random access channel (RACH) procedureon CC2 may be used for CC1 beam recovery. The RACH based solution may beused in general, or in combination with the previous examples. Forinstance, a UE 115 may selects one of the previous examples if it is ULtime synchronized in CC2 and may select the RACH based beam recoverytransmission on CC2 if it is not UL time synchronized.

In some cases, a RACH procedure on CC2 can be a contention free randomaccess (CFRA) procedure. A preamble can be assigned to a UE 115 on CC2for conveying beam recovery signal on CC. Upon receiving Msg1 of CFRA onCC2, a base station 105 may identify the UE 115 that wants to conveybeam recovery or scheduling request on CC1 but may not know the beam IDthat the UE 115 wants to convey. In this situation, the base station 105response may be similar to that described in the second example.Alternatively, a set of preambles can be assigned to a UE 115 on CC2 forconveying beam recovery signal on CC1. Each preamble in the set may bemapped to a different beam on CC1. Upon receiving preamble (Msg1) ofCFRA on CC2, the base station 105 may uniquely identify the beam for theUE 115. In this situation, the base station 105 response may be similarto that described in the first example.

In other cases, a RACH procedure on CC2 can be a contention based randomaccess (CBRA). In this case, the UE 115 may convey through Msg3 that ittransmitted RACH to request beam recovery on CC1. Msg3 may conveys 1 bitindicating a UE's reason to transmit RACH. In this situation, the basestation 105 response may be similar to that described in the secondexample. A separate time-frequency region may be reserved for contentionbased PRACH on CC2 to convey beam recovery signal on CC1. Upon receivingMsg1, the base station 105 may realize that this RACH on CC2 wastransmitted to convey beam recovery for CC1. After the completion ofMsg3/Msg4 of this procedure, the base station 105 may realize which UE115 conveyed this request. In any of the examples discussed above, thenumber of retransmissions in CC1 used to convey beam recovery request onCC1 may be limited to a maximum number.

The number of beam failure recovery request transmissions may beconfigurable by using parameters such as the number of transmissions, atimer, or a combination thereof. In case of unsuccessful recovery frombeam failure, a UE 115 may sends an indication to higher layers, andrefrain from further beam failure recovery. The same parameters may alsobe used to define maximum number of retransmissions on CC2 to conveybeam recovery request for CC1, after which UE 115 sends an indication tohigher layers and refrains from further beam recovery. In some cases,the values for timer and number of retransmissions could be differentbetween CC2 and CC1. The numerology (tone spacing, symbol and slotduration, etc.) could also be different between CC2 and CC1. In somecases, CC1 may use an over-6 GHz frequency band and may use shortersymbol or slot duration, while CC2 uses sub-6 GHz band and longer symbolor slot duration.

In some cases, a base station 105 may configure the same number ofretransmissions on CC2 as it would have done in CC1. Then the UE 115 mayhave to wait for a long time before it can refrain from further beamrecovery. Hence, a base station 105 can configure different maximumretransmission limits for CC1 and CC2 if the UE 115 wants to convey beamrecovery request for CC1. For example, a base station 105 can configureN1 retransmissions and N2 retransmissions on CC1 and CC2, respectively,if UE 115 wants to convey beam recovery request for CC1. In other words,if a UE 115 conveys beam recovery request for CC1 in CC2, it canretransmit it N2 times before sending an indication to upper layers. IfUE 115 conveys beam recovery request for CC1 in CC1, it can retransmitit N1 times before sending the indication. In many examples, N1 would begreater N2.

In another example, a base station 105 can configure a timer for the UE115 to convey beam recovery request for CC1. It can be left up to UE 115implementation to determine which CC (CC1 or CC2) it uses to convey beamrecovery request for CC1. In some cases, a maximum number ofretransmissions will depend on UE's number of selections for CC1 andCC2. The UEs 115 may be dispersed throughout the wireless communicationnetwork, and each UE 115 may be stationary or mobile.

FIG. 2 shows a spectrum diagram 200 that illustrates aspects of thefrequency range in which some of the communications described herein areperformed in accordance with aspects of the present disclosure. Spectrumdiagram 200 may include the following components: electromagneticspectrum 202 and environment 228.

In some examples, electromagnetic spectrum 202 may include the followingcomponents: ultra-violet (UV) radiation 204, visible light 206, infraredradiation 208, and radio waves 210. The MMW (or extremely high frequency(EHF)) portion of the electromagnetic spectrum corresponds toelectromagnetic radiation with a frequency of 30-300 GHz and awavelength between 1 mm and 1 cm. Near MMW may extend down to afrequency of 3 GHz with a wavelength of 100 millimeters.

In some examples, radio waves 210 may include the following components:EHF band 212, super high frequency (SHF) band 214, ultra high frequency(UHF) band 216, very high frequency (VHF) band 218, high frequency (HF)band 220, medium frequency (MF) band 222, low frequency (LF) band 224,and very low frequency (VLF) band 226. The EHF band 212 lies between theSHF band 214 and the far infrared band. The SHF band 214 may also bereferred to as the centimeter wave band.

In some examples, environment 228 may include the following components:MMW radiation 230, atmosphere 232, rain 234, obstacle 236, and foliage238. MMW radiation 230 may be subject to substantial absorption andscattering by atmospheric gases (especially oxygen), foliage 238, rain234, and other environmental factors. In some cases, a wirelesscommunications network may operate using MMW radiation 230. However, therange of MMW communications may be limited by relatively high path lossand, in some cases, short range. Thus, base stations in networksutilizing MMW transmissions may be more densely packed, or may usetechniques such as beamforming to compensate. The short wavelength ofMMW transmissions compared to lower frequency bands may enablebeamforming in devices that have a relatively small antenna array.

FIG. 3 shows a schematic diagram 300 that supports performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure. Specifically, schematic diagram 300 illustrates anexample of beamforming operations, and may include the followingcomponents: base station 105, beamforming pattern 320, and UE 115.

Base station 105 may incorporate aspects of the base stations describedwith reference to FIGS. 1, 5, and 6. In some examples, base station 105may include beamforming array 310. In some examples, beamforming array310 may include one or more antennas 315. UE 115 may incorporate aspectsof the UEs described with reference to FIGS. 1, 5, and 6. In someexamples, UE 115 may include a transceiver. The transceiver mayincorporate aspects of the transceiver described with reference to FIGS.5 and 6. In some cases, a transceiver may perform some of the functionsdescribed herein as being performed by UE 115. In some examples, thetransceiver may be tuned to operate at specified frequencies.

Beamforming is a technique for directional signal transmission andreception. Beamforming at a transmitter may involve phase-shifting thesignal produced at different antennas 315 in an array to focus atransmission in a particular direction. The phase-shifted signals mayinteract to produce constructive interference in certain directions anddestructive interference in other directions. By focusing the signalpower, a transmitter may improve communication throughput while reducinginterference with neighboring transmitters.

Similarly, beamforming at a receiver may involve phase-shifting a signalreceived at different antennas 315. When combining the phase shiftedsignals, the receiver may amplify a signal from certain directions andreduce the signal from other directions. In some cases, receivers andtransmitters may utilize beamforming techniques independently of eachother. In other cases, a transmitter and receiver may coordinate toselect a beam 325 direction. The use of beamforming may depend onfactors such as the type of signal being transmitted and the channelconditions. For example, directional transmissions may not be usefulwhen transmitting to multiple receivers, or when the location of thereceiver is unknown. Thus, beamforming may be appropriate for unicasttransmissions, but may not be useful for broadcast transmissions. Also,beamforming may be appropriate when transmitting in a high frequencyradio band, such as in the MMW band.

Since the beamforming array 310 size is proportional to the signalwavelength, smaller devices may be capable of beamforming in highfrequency bands. Also, the increased receive power may compensate forthe increased path loss at these frequencies. In some examples,beamforming pattern 320 may include one or more beams 325, which may beidentified by individual beam IDs.

FIG. 4 shows a beam recovery configuration that supports performing abeam recovery procedure using a second CC in accordance with aspects ofthe present disclosure. Specifically, using synchronization signal (SS)and SR-RS resources QCL with the SS. Beam recovery configuration mayinclude the following components: burst set 405 and BR-SR slot 415. Insome examples, burst set 405 may include one or more synchronizationsignal SS blocks 410. In some examples, BR-SR slot 415 may include BR-SRsignal 420 and RACH signal 425. As described in the present disclosure,a beam recovery procedure for a first CC may utilize resources on asecond CC associated with either BR-SR signals 420, RACH signals 425, orboth.

FIG. 5 shows a schematic diagram 500 that supports performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure. Schematic diagram 500 may include the followingcomponents: UE 115, gateway 504, network 506, UL communications 508,downlink (DL) communications 510, and base station 512.

UE 115 may incorporate aspects of the UEs described with reference toFIGS. 1, 3, and 6. A gateway 504 may comprise a software and/or hardwarefirewall that may be used to selectively route information from anaccess network to a core network and beyond. Thus, a gateway 504functions to block various external data transmissions from being sentto certain internal locations. In this regard, a gateway 504 may berestrictively configured to allow remotely situated users to accesscontent such as web pages within a computer system or network 506 (e.g.,via hypertext transfer protocol (HTTP) protocols) and to block all otheraccess. A gateway 504 may also provide a port for outgoing Internettraffic. A gateway 504 may be further configured to internally routeIP-Packets.

The network 506 may include a number of interconnected communicationsdevices. For example, the network 506 may represent the internet or anoperator specific communications system.

Base station 105 may incorporate aspects of the base stations describedwith reference to FIGS. 1, 3, and 6. In some examples, base station 105may include the following components: transceiver 514, radio frequency(RF) front end 520, antenna array 532, memory 534, and processor 536.

Transceiver 514 may incorporate aspects of the transceiver withreference to FIGS. 3 and 6. In some examples, transceiver 514 mayinclude the following components: TX radio 516 and RX radio 518.

TX radio 516 may include hardware, firmware, and/or software codeexecutable by a processor 536 for transmitting data, the code comprisinginstructions and being stored in a memory 534 (e.g., computer-readablemedium). A suitable example of TX radio 516 may including, but is notlimited to, an RF transmitter.

RX radio 518 may include hardware, firmware, and/or software codeexecutable by a processor 536 for receiving data, the code comprisinginstructions and being stored in a memory 534 (e.g., computer-readablemedium). RX radio 518 may be, for example, an RF receiver. In an aspect,receiver may receive signals transmitted by at least one base station512. Additionally, an RX radio 518 may process such received signals,and also may obtain measurements of the signals including, but notlimited to, signal-to-noise ratio (SNR), RSRP, received signal strengthindicator (RSSI), etc.

In some examples, RF front end 520 may include the following components:input switch 522, radio switches 524, low noise amplifier (LNA) 526,power amplifier (PA) 528, and filter 530. RF front end 520 may operatein communication with one or more antennas and transceiver 514 forreceiving and transmitting radio transmissions, for example, wirelesscommunications between base station 105 and UE 115. RF front end 520 mayoperate in communication with one or more antennas and transceiver 514for receiving and transmitting radio transmissions, for example,wireless communications between base station 105 and UE 115.

An input switch 522 may be used to select one or more antennas. Radioswitches 524 may connect or disconnect one or more RX radios 518 or TXradios 516. In an aspect, RF front end 520 may also use one or moreradio switches 524 to select a particular LNA 526 or PA 528 and itsspecified gain value based on a desired gain value for a particularapplication.

LNA 526 may amplify a received signal at a desired output level. In anaspect, each LNA 526 may have a specified minimum and maximum gainvalues. One or more PAs 528 may be used by RF front end 520 to amplify asignal for an RF output at a desired output power level. In an aspect,each PA 528 may have specified minimum and maximum gain values.

Filter 530 may selectively suppress aspects of a signal. For example,one or more filters 530 can be used by RF front end 520 to filter 530 areceived signal to obtain an input RF signal. Similarly, in an aspect,for example, a respective filter 530 can be used to filter 530 an outputfrom a respective PA 528 to produce an output signal for transmission.In an aspect, each filter 530 can be connected to a specific LNA 526and/or PA 528. In an aspect, RF front end 520 can use one or moreswitches to select a transmit or receive path using a specified filter530, LNA 526, and/or PA 528, based on a configuration as specified bytransceiver 514 and/or processor 536.

Antenna array 532 may include one or more antennas and be capable ofconcurrently transmitting or receiving multiple wireless transmissions.

A memory 534 may be configured to store data and/or local versions ofapplications described herein. Memory 534 can include any type ofcomputer-readable medium usable by a computer or at least one processor536, such as random access memory (RAM), read only memory (ROM), tapes,magnetic discs, optical discs, volatile memory 534, non-volatile memory534, and any combination thereof. For example, memory 534 may be anon-transitory computer-readable storage medium that stores one or morecomputer-executable codes for performing the functions described hereinwhen a processor 536 executes these functions.

In some examples, processor 536 may include modem 538. The one or moreprocessors 536, modem 538, memory 534, transceiver 514, RF front end 520and one or more antennas, may be configured to support voice and/or datacalls (simultaneously or non-simultaneously) in one or more radio accesstechnologies. In some cases, these components may communicate via one ormore busses. In some cases, the functions described herein be executedby a single processor 536, while in other cases, different ones of thefunctions may be executed by a combination of two or more differentprocessors 536. For example, in an aspect, the one or more processors536 may include components for modulation, demodulation, basebandprocessing, digital signal processing, transmitter processing, receiverprocessing and may operate as part of or in conjunction with atransceiver 514.

In some examples, modem 538 may include access communications managementcomponent 540. Modem 538 can configure transceiver 514 to operate at aspecified frequency and power level based on a communicationconfiguration and protocol. In an aspect, modem 538 can be amultiband-multimode device which can process digital data andcommunicate with transceiver 514 such that the digital data is sent andreceived using transceiver 514. In an aspect, modem 538 can be multibandand be configured to support multiple frequency bands for a specificcommunications protocol. In an aspect, modem 538 can be multimode and beconfigured to support multiple operating networks 506 and communicationsprotocols. In an aspect, modem 538 can control one or more componentssuch as RF front end 520 or transceiver 514 to enable transmissionand/or reception of signals based on a specified modem 538configuration. In an aspect, the modem 538 configuration can be based onthe mode of the modem 538 and the frequency band in use. In anotheraspect, the modem 538 can be configured be based on configurationinformation associated with a network 506 (e.g., information determinedduring cell selection and/or cell reselection).

Access communications management component 540 may establishcommunication with a UE 115 over a first component carrier using one ormore beams and communicate with the UE 115 over the first componentcarrier using the candidate beam. In some examples, accesscommunications management component 540 may include the followingcomponents: BS-SR component 542, beam selection component 544, and RACHcomponent 546. In some cases, the first component carrier is a MMWcarrier and the second component carrier is a sub-6 GHz carrier.

BS-SR component 542 may receive a BR-SR from the UE 115 over a secondcomponent carrier in response to the UE 115 initiating beam recovery. Insome cases, receiving the BR-SR from the UE 115 over the secondcomponent carrier comprises: receiving a beam measurement report for thefirst component carrier along with the BR-SR to the base station 105 onthe second component carrier on resources allocated to the UE 115 foruplink transmission on the second component carrier. In some cases,receiving the BR-SR from the UE 115 over the second component carriercomprises: receiving a logical signal from the UE 115 that indicatesthat the UE 115 has triggered beam recovery for the first componentcarrier. In some cases, receiving the BR-SR from the UE 115 comprises:receiving at least one or more of a beam ID of the candidate beam in theBR-SR. In some cases, the beam measurement report comprises at least oneor more of a beam ID of the candidate beam or the beam ID of a currentactive beam.

Beam selection component 544 may identify a candidate beam on the firstcomponent carrier based on the BR-SR received on the second componentcarrier; transmit a request from the base station 512 to the UE 115 fora beam measurement report for the first component carrier in response toreceiving the BR-SR from the UE 115; and transmit a beam switch commandfrom the base station 105 to the UE 115, wherein the beam switch commandinstructs the UE 502 to switch active communication from the one or morebeams to the candidate beam.

RACH component 546 may utilize a random access procedure on the secondcomponent carrier for beam recovery on the first component carrier.

FIG. 6 shows a schematic diagram 600 that supports performing a beamrecovery procedure using a second CC in accordance with aspects of thepresent disclosure. Schematic diagram 600 may include the followingcomponents: base station 105, gateway 604, network 606, ULcommunications 608, DL communications 610, and UE 115.

Base station 105 may incorporate aspects of the base stations describedwith reference to FIGS. 1, 3, and 5.

Gateway 604, Network 606, UL communications 608, and DL communications610 may incorporate aspects of the corresponding components of the samename described with reference to FIG. 5.

UE 115 may incorporate aspects of the UEs described with reference toFIGS. 1, 3, and 5. In some examples, UE 115 may include the followingcomponents: transceiver 614, RF front end 620, antenna array 632, memory634, and processor 636.

Transceiver 614 may incorporate aspects of the transceiver describedwith reference to FIGS. 3 and 5. In some examples, transceiver 614 mayinclude the following components: TX radio 616 and RX radio 618.

TX radio 616, RX radio 618, and RF front end 620 may incorporate aspectsof the corresponding components of the same name described withreference to FIG. 5. In some examples, RF front end 620 may include thefollowing components: input switch 622, radio switches 624, LNA 626, PA628, and filter 630.

Input switch 622, Radio switches 624, LNA 626, PA 628, Filter 630,Antenna array 632, Memory 634, and Processor 636 may incorporate aspectsof the corresponding components of the same name described withreference to FIG. 5. In some examples, processor 636 may include modem638.

Modem 638 may incorporate aspects of the modem described with referenceto FIG. 5. In some examples, modem 638 may include mobile communicationsmanagement component 640. Mobile communications management component 640may communicate with a base station 105 over a first component carrierusing one or more beams. In some examples, mobile communicationsmanagement component 640 may include the following components: beamrecovery component 642, beam candidate component 644, UE BS-SRcomponent, monitoring component 648, and beam measurement component 650.

Beam recovery component 642 may determine to trigger beam recovery forthe first component carrier.

Beam candidate component 644 may identify a candidate beam forcommunication with the base station 105 based on the determining.

UE BS-SR component may transmit a BR-SR from the UE 115 to the basestation 105 over a second component carrier to signal beam recovery forthe first component carrier; and transmit the beam measurement reportfor the first component carrier along with the BR-SR to the base station105 on the second component carrier on resources allocated for uplinktransmission on the second component carrier.

In some cases, transmitting the BR-SR from the UE 115 to the basestation 602 over the second component carrier comprises: generating abeam measurement report regarding the first component carrier. In somecases, transmitting the BR-SR from the UE 612 to the base station 602over the second component carrier comprises: transmitting a logicalsignal from the UE 115 that indicates that the UE 115 has triggered beamrecovery for the first component carrier. In some cases, transmittingthe BR-SR from the UE 115 to the base station 105 comprises:transmitting at least one or more of a beam ID of the candidate beam inthe BR-SR.

In some cases, the beam measurement report is generated by a MAC layerof the UE 612 and multiplexed with uplink data on PUSCH of the secondcomponent carrier. In some cases, the beam measurement report comprisesat least one or more of a beam ID of the candidate beam or the beam IDof a current active beam. In some cases, the beam measurement reportcomprises a beam strength measurement for the candidate beam.

Monitoring component 648 may monitor the first component carrier on theone or more beams for a trigger to generate a beam measurement report inresponse to transmitting the logical signal from the UE 115 thatindicates that the UE 115 has triggered beam recovery for the firstcomponent carrier; monitor PDCCH on the second component carrier for DCIrelated to the first component carrier in response to transmitting theBR-SR to the base station 602; and monitor the second component carrierfor beam switch command from the base station 105 in response totransmitting the BR-SR to the base station 105, wherein the beam switchcommand requests the UE 115 to switch communication to the candidatebeam.

Beam measurement component 650 may receive a request from the basestation 105 for a beam measurement report for the first componentcarrier; generate the beam measurement report regarding the firstcomponent carrier in response to receiving the request; and transmit thebeam measurement report regarding the first component carrier to thebase station 105 over the second component carrier.

FIG. 7 shows a flowchart 700 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, the features of flowchart 700 may beperformed by the base station 105. In some examples, a system orapparatus may execute a set of codes to control the functional elementsof the device to perform the described functions. Additionally oralternatively, the system or apparatus may perform aspects of thefunctions described below using special-purpose hardware.

At block 705 the system or apparatus may establish communication with aUE over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby an access communications management component 540 as described withreference to FIG. 5.

At block 710 the system or apparatus may receive a signal from the UEover a second component carrier in response to the UE initiating beamrecovery. The signal from the UE may be either a beam recoveryscheduling request (BR-SR) or a scheduling request (SR). Specifically,in some examples, instead of transmitting the complete BR-SR signal, theUE BR-SR signal may be similar to a regular SR signal and CDMed (CodeDivision Multiplexed), FDMed (Frequency Division Multiplexed) or TDMed(Time Division Multiplexed) with regular SR or with PRACH. (e.g., BR-SRsignal that may be based on a different sequence than that of theregular SR or the PRACH). In such example, BR-SR may serve as a logicalbeam trigger signal (e.g., 1 bit) that signals to the base station thata beam recovery has been triggered by the UE. The operations of thisblock may be performed according to the methods and processes describedin the present disclosure. For example, the operations of this block maybe composed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a BS-SR component 542 inconjunction with transceiver 514 as described with reference to FIG. 5.

At block 715 the system or apparatus may identify a candidate beam onthe first component carrier based on the BR-SR received on the secondcomponent carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam selection component 544as described with reference to FIG. 5.

At block 720 the system or apparatus may communicate with the UE overthe first component carrier using the candidate beam. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an accesscommunications management component 540 as described with reference toFIG. 5.

FIG. 8 shows a flowchart 800 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, the features of flowchart 700 may beperformed by the base station 105. In some examples, a system orapparatus may execute a set of codes to control the functional elementsof the device to perform the described functions. Additionally oralternatively, the system or apparatus may perform aspects of thefunctions described below using special-purpose hardware.

At block 805 the system or apparatus may establish communication with aUE over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby an access communications management component 540 as described withreference to FIG. 5.

At block 810 the system or apparatus may receive a beam measurementreport for the first component carrier along with the BR-SR to the basestation on the second component carrier on resources allocated to the UEfor uplink transmission on the second component carrier. The operationsof this block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by a BS-SRcomponent 542 in conjunction with transceiver 514 as described withreference to FIG. 5.

At block 815 the system or apparatus may identify a candidate beam onthe first component carrier based on the beam measurement reportreceived on the second component carrier. The operations of this blockmay be performed according to the methods and processes described in thepresent disclosure. For example, the operations of this block may becomposed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam selection component 544as described with reference to FIG. 5.

At block 820 the system or apparatus may communicate with the UE overthe first component carrier using the candidate beam. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an accesscommunications management component 540 as described with reference toFIG. 5.

FIG. 9 shows a flowchart 900 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 905 the system or apparatus may establish communication with aUE over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby an access communications management component 540 as described withreference to FIG. 5.

At block 910 the system or apparatus may receive a logical signal fromthe UE that indicates that the UE has triggered beam recovery for thefirst component carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by a BS-SR component 542 asdescribed with reference to FIG. 5.

At block 915 the system or apparatus may identify a candidate beam onthe first component carrier based on the logical signal received on thesecond component carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam selection component 544as described with reference to FIG. 5.

At block 920 the system or apparatus may communicate with the UE overthe first component carrier using the candidate beam. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an accesscommunications management component 540 as described with reference toFIG. 5.

FIG. 10 shows a flowchart 1000 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1005 the system or apparatus may establish communication with aUE over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby an access communications management component 540 as described withreference to FIG. 5.

At block 1010 the system or apparatus may receive at least one or moreof a beam identification ID of the candidate beam in a BR-SR. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a BS-SR component 542 as described with reference to FIG. 5.

At block 1015 the system or apparatus may identify a candidate beam onthe first component carrier based on the BR-SR received on the secondcomponent carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam selection component 544as described with reference to FIG. 5.

At block 1020 the system or apparatus may communicate with the UE overthe first component carrier using the candidate beam. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an accesscommunications management component 540 as described with reference toFIG. 5.

FIG. 11 shows a flowchart 1100 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1105 the system or apparatus may establish communication with aUE over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby an access communications management component 540 as described withreference to FIG. 5.

At block 1110 the system or apparatus may receive a BR-SR from the UEover a second component carrier in response to the UE initiating beamrecovery by utilizing the random access procedure. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by a BS-SRcomponent and RACH component 546, as described with reference to FIG. 5.

At block 1120 the system or apparatus may identify a candidate beam onthe first component carrier based on the BR-SR received on the secondcomponent carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam selection component 544as described with reference to FIG. 5.

At block 1125 the system or apparatus may communicate with the UE overthe first component carrier using the candidate beam. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an accesscommunications management component 540 as described with reference toFIG. 5.

FIG. 12 shows a flowchart 1200 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1205 the system or apparatus may communicate with a basestation over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a mobile communications management component 640 as described withreference to FIG. 6.

At block 1210 the system or apparatus may determine to trigger beamrecovery for the first component carrier. The operations of this blockmay be performed according to the methods and processes described in thepresent disclosure. For example, the operations of this block may becomposed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam recovery component 642as described with reference to FIG. 6.

At block 1215 the system or apparatus may identify a candidate beam forcommunication with the base station based on the determining. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a beam candidate component 644 as described with reference to FIG. 6.

At block 1220 the system or apparatus may transmit a signal from the UEto the base station over a second component carrier to signal beamrecovery for the first component carrier. The signal from the UE may beeither a beam recovery scheduling request (BR-SR) or a schedulingrequest (SR). The operations of this block may be performed according tothe methods and processes described in the present disclosure. Forexample, the operations of this block may be composed of varioussubsteps, or may be performed in conjunction with other operationsdescribed herein. In certain examples, aspects of the describedoperations may be performed by an UE BS-SR component 646 as describedwith reference to FIG. 6.

FIG. 13 shows a flowchart 1300 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1305 the system or apparatus may communicate with a basestation over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a mobile communications management component 640 as described withreference to FIG. 6.

At block 1310 the system or apparatus may determine to trigger beamrecovery for the first component carrier. The operations of this blockmay be performed according to the methods and processes described in thepresent disclosure. For example, the operations of this block may becomposed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam recovery component 642as described with reference to FIG. 6.

At block 1315 the system or apparatus may identify a candidate beam forcommunication with the base station based on the determining. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a beam candidate component 644 as described with reference to FIG. 6.

At block 1320 the system or apparatus may generate a beam measurementreport regarding the first component carrier. The operations of thisblock may be performed according to the methods and processes describedin the present disclosure. For example, the operations of this block maybe composed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by an UE BS-SR component 646 asdescribed with reference to FIG. 6.

At block 1325 the system or apparatus may transmit the beam measurementreport for the first component carrier along with the BR-SR to the basestation on the second component carrier on resources allocated foruplink transmission on the second component carrier. The operations ofthis block may be performed according to the methods and processesdescribed in the present disclosure. For example, the operations of thisblock may be composed of various substeps, or may be performed inconjunction with other operations described herein. In certain examples,aspects of the described operations may be performed by an UE BS-SRcomponent 646 as described with reference to FIG. 6.

FIG. 14 shows a flowchart 1400 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1405 the system or apparatus may communicate with a basestation over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a mobile communications management component 640 as described withreference to FIG. 6.

At block 1410 the system or apparatus may determine to trigger beamrecovery for the first component carrier. The operations of this blockmay be performed according to the methods and processes described in thepresent disclosure. For example, the operations of this block may becomposed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam recovery component 642as described with reference to FIG. 6.

At block 1415 the system or apparatus may identify a candidate beam forcommunication with the base station based on the determining. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a beam candidate component 644 as described with reference to FIG. 6.

At block 1420 the system or apparatus may transmit a logical signal fromthe UE that indicates that the UE has triggered beam recovery for thefirst component carrier. The operations of this block may be performedaccording to the methods and processes described in the presentdisclosure. For example, the operations of this block may be composed ofvarious substeps, or may be performed in conjunction with otheroperations described herein. In certain examples, aspects of thedescribed operations may be performed by an UE BS-SR component 646 asdescribed with reference to FIG. 6.

FIG. 15 shows a flowchart 1500 that supports performing a beam recoveryprocedure using a second CC in accordance with aspects of the presentdisclosure. In some examples, a system or apparatus may execute a set ofcodes to control the functional elements of the device to perform thedescribed functions. Additionally or alternatively, the system orapparatus may perform aspects of the functions described below usingspecial-purpose hardware.

At block 1505 the system or apparatus may communicate with a basestation over a first component carrier using one or more beams. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a mobile communications management component 640 as described withreference to FIG. 6.

At block 1510 the system or apparatus may determine to trigger beamrecovery for the first component carrier. The operations of this blockmay be performed according to the methods and processes described in thepresent disclosure. For example, the operations of this block may becomposed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by a beam recovery component 642as described with reference to FIG. 6.

At block 1515 the system or apparatus may identify a candidate beam forcommunication with the base station based on the determining. Theoperations of this block may be performed according to the methods andprocesses described in the present disclosure. For example, theoperations of this block may be composed of various substeps, or may beperformed in conjunction with other operations described herein. Incertain examples, aspects of the described operations may be performedby a beam candidate component 644 as described with reference to FIG. 6.

At block 1520 the system or apparatus may transmit at least one or moreof a beam ID of the candidate beam in the BR-SR. The operations of thisblock may be performed according to the methods and processes describedin the present disclosure. For example, the operations of this block maybe composed of various substeps, or may be performed in conjunction withother operations described herein. In certain examples, aspects of thedescribed operations may be performed by an UE BS-SR component 646 asdescribed with reference to FIG. 6.

FIG. 16 shows a method 1600 that supports wireless communication overmultiple component carriers. In some examples, a system or apparatus mayexecute a set of codes to control the functional elements of the deviceto perform the described functions. Additionally or alternatively, thesystem or apparatus may perform aspects of the functions described belowusing special-purpose hardware.

At block 1605, the method 1600 may include establishing communicationwith a UE over a first component carrier. In certain examples, aspectsof the described operations may be performed by an access communicationsmanagement component 540 as described with reference to FIG. 5.

At block 1610, the method 1600 may include transmitting a configurationmessage from the base station to the UE in order to configuresupplemental communication over a second component carrier. In someexamples, the configuration message may configure the second componentcarrier as an assisting carrier that may be utilized in order totransmit or receive one or more of beam failure indication, beamreporting, and/or beam switch indication between the base station andthe UE as it relates to the first component carrier. In certainexamples, aspects of the described operations may be performed by atransceiver 514 as described with reference to FIG. 5.

At block 1615, the method 1600 may include transmitting a first messageto the UE over the first component carrier. The first message may becommunications between the base station and the UE over the firstcomponent carrier. In certain examples, aspects of the describedoperations may be performed by a transceiver 514 as described withreference to FIG. 5.

At block 1620, the method 1600 may include transmitting a second messageto the UE over the second component carrier. The second message may beone or more of beam failure indication, beam reporting, or beam switchindication transmitted on the second component carrier. It should beappreciated that the features of the present disclosure are notnecessarily limited to instances following the UE initiating beamrecovery. Instead, the second component carrier (e.g., assistingcarrier) may be employed to independently transmit or receive beamfailure indication, beam reporting (e.g., candidate beams), or beamswitch indication (without the need for beam failure to first occur). Incertain examples, aspects of the described operations may be performedby a transceiver 514 as described with reference to FIG. 5.

FIG. 17 shows a method 1700 that supports wireless communication overmultiple component carriers. In some examples, a system or apparatus mayexecute a set of codes to control the functional elements of the deviceto perform the described functions. Additionally or alternatively, thesystem or apparatus may perform aspects of the functions described belowusing special-purpose hardware.

At block 1705, the method 1600 may include establishing communicationwith a base station over a first component carrier. In certain examples,aspects of the described operations may be performed by mobilecommunications management component 640 as described with reference toFIG. 6.

At block 1710, the method 1600 may include receiving a configurationmessage from the base station at the UE in order to configuresupplemental communication over a second component carrier. In someexamples, the configuration message may configure the second componentcarrier as an assisting carrier that may be utilized in order totransmit or receive one or more of beam failure indication, beamreporting, and/or beam switch indication between the base station andthe UE as it relates to the first component carrier. In certainexamples, aspects of the described operations may be performed by atransceiver 614 as described with reference to FIG. 6.

At block 1715, the method 1600 may include receiving a first message tothe UE over the first component carrier. In certain examples, aspects ofthe described operations may be performed by a transceiver 614 asdescribed with reference to FIG. 6.

At block 1720, the method 1600 may include receiving a second message tothe UE over the second component carrier. The second message may be oneor more of beam failure indication, beam reporting, or beam switchindication transmitted on the second component carrier. It should beappreciated that the features of the present disclosure are notnecessarily limited to instances following the UE initiating beamrecovery. Instead, the second component carrier (e.g., assistingcarrier) may be employed to independently transmit or receive beamfailure indication, beam reporting (e.g., candidate beams), or beamswitch indication (without the need for beam failure to first occur). Incertain examples, aspects of the described operations may be performedby a transceiver 614 as described with reference to FIG. 6.

The above detailed description set forth above in connection with theappended drawings describes examples and does not represent the onlyexamples that may be implemented or that are within the scope of theclaims. The term “example,” when used in this description, means“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, computer-executable code or instructionsstored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with aspecially-programmed device, such as but not limited to a processor, adigital signal processor (DSP), an ASIC, a FPGA or other programmablelogic device, a discrete gate or transistor logic, a discrete hardwarecomponent, or any combination thereof designed to perform the functionsdescribed herein. A specially-programmed processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aspecially-programmed processor may also be implemented as a combinationof computing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

It should be noted that the techniques described herein may be used forvarious wireless communication networks such as CDMA, TDMA, FDMA, OFDMA,SC-FDMA, and other systems. The terms “system” and “network” are oftenused interchangeably. A CDMA system may implement a radio technologysuch as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0and A are commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856)is commonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data(HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants ofCDMA. A TDMA system may implement a radio technology such as GlobalSystem for Mobile Communications (GSM). An OFDMA system may implement aradio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA(E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Flash-OFDM™, etc. UTRA and E-UTRA are part of Universal MobileTelecommunication System (UMTS). 3GPP Long Term Evolution (LTE) andLTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA,E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from anorganization named “3rd Generation Partnership Project” (3GPP). CDMA2000and UMB are described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). The techniques describedherein may be used for the systems and radio technologies mentionedabove as well as other systems and radio technologies, includingcellular (e.g., LTE) communications over a shared radio frequencyspectrum band. The description below, however, describes an LTE/LTE-Asystem for purposes of example, and LTE terminology is used in much ofthe description below, although the techniques are applicable beyondLTE/LTE-A applications (e.g., to 5G networks or other next generationcommunication systems).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on anon-transitory computer-readable medium. Other examples andimplementations are within the scope and spirit of the disclosure andappended claims. For example, due to the nature of software, functionsdescribed above can be implemented using software executed by aspecially programmed processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items prefaced by “at least one of” indicates a disjunctivelist such that, for example, a list of “at least one of A, B, or C”means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the common principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Furthermore, although elements of the describedaspects and/or embodiments may be described or claimed in the singular,the plural is contemplated unless limitation to the singular isexplicitly stated. Additionally, all or a portion of any aspect and/orembodiment may be utilized with all or a portion of any other aspectand/or embodiment, unless stated otherwise. Thus, the disclosure is notto be limited to the examples and designs described herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communications at a basestation, comprising: establishing direct wireless communication with auser equipment (UE) over a first component carrier using one or morebeams; wirelessly receiving a signal directly from the UE over a secondcomponent carrier in response to the UE initiating beam recovery;identifying a candidate beam on the first component carrier based on thesignal received on the second component carrier; and wirelesslycommunicating directly with the UE over the first component carrierusing the candidate beam.
 2. The method of claim 1, wherein: receivingthe signal from the UE over the second component carrier comprisesreceiving a beam measurement report for the first component carrier onthe second component carrier on resources allocated to the UE for uplinktransmission on the second component carrier.
 3. The method of claim 2,wherein: receiving a beam measurement report comprises receiving an SRon the resources allocated to the UE for SR, and allocating to the UEthe resources for transmitting the beam measurement report.
 4. Themethod of claim 2, wherein: the beam measurement report comprises atleast one or more of a beam identification (ID) of the candidate beam orthe beam ID of a current active beam.
 5. The method of claim 1, whereinthe signal from the UE identifies that the UE has initiated beamrecovery is either a beam recovery scheduling request (BR-SR) or ascheduling request (SR).
 6. The method of claim 1, further comprising:transmitting a request from the base station to the UE for a beammeasurement report for the first component carrier in response toreceiving the signal from the UE.
 7. The method of claim 1, furthercomprising: transmitting a beam switch command from the base station tothe UE, wherein the beam switch command instructs the UE to switchactive communication from the one or more beams to the candidate beam.8. The method of claim 1, wherein: receiving the signal from the UEcomprises: receiving at least one or more of a beam ID of the candidatebeam in the signal.
 9. The method of claim 1, further comprising:utilizing a random access random access channel (RACH) on the secondcomponent carrier for beam recovery on the first component carrier. 10.The method of claim 1, wherein: the first component carrier is amillimeter wave (MMW) carrier and the second component carrier is asub-6 GHz carrier.
 11. The method of claim 1, wherein the signal fromthe UE corresponds to a random access channel (RACH) procedure on thesecond component carrier.
 12. A method for wireless communications at auser equipment (UE), comprising: wirelessly communicating directly witha base station over a first component carrier using one or more beams;determining to trigger beam recovery for the first component carrier;identifying a candidate beam for direct wireless communication with thebase station based on the determining; and wirelessly transmitting asignal directly from the UE to the base station over a second componentcarrier to signal beam recovery for the first component carrier.
 13. Themethod of claim 12, wherein: transmitting the signal from the UE to thebase station over the second component carrier comprises generating abeam measurement report regarding the first component carrier; andtransmitting the beam measurement report for the first component carrieralong with the BR-SR to the base station on the second component carrieron resources allocated for uplink transmission on the second componentcarrier.
 14. The method of claim 13, wherein: the beam measurementreport is generated by a media access control (MAC) layer of the UE andmultiplexed with uplink data on physical uplink shared channel (PUSCH)of the second component carrier.
 15. The method of claim 13, wherein:the beam measurement report comprises at least one or more of a beam IDof the candidate beam or the beam ID of a current active beam.
 16. Themethod of claim 13, wherein: the beam measurement report comprises abeam strength measurement for the candidate beam.
 17. The method ofclaim 12, wherein the signal from the UE identifies that the UE hasinitiated beam recovery on the first component carrier is either a beamrecovery scheduling request (BR-SR) or a scheduling request (SR). 18.The method of claim 17, further comprising: monitoring the firstcomponent carrier on the one or more beams for a trigger to generate abeam measurement report in response to transmitting the signal from theUE that indicates that the UE has triggered beam recovery for the firstcomponent carrier.
 19. The method of claim 12, further comprising:receiving a request from the base station for a beam measurement reportfor the first component carrier; generating the beam measurement reportregarding the first component carrier in response to receiving therequest; and wirelessly transmitting the beam measurement reportregarding the first component carrier directly to the base station overthe second component carrier.
 20. The method of claim 12, wherein thesignal comprises a beam recovery scheduling request (BR-SR), and furthercomprising: monitoring physical downlink control channel (PDCCH) on thesecond component carrier for downlink control information (DCI) relatedto the first component carrier.
 21. The method of claim 12, wherein thesignal comprises a beam recovery scheduling request (BR-SR), and furthercomprising: monitoring the second component carrier for beam switchcommand from the base station, wherein the beam switch command requeststhe UE to switch communication to the candidate beam.
 22. The method ofclaim 12, wherein the signal comprises a beam recovery schedulingrequest (BR-SR) indicating a beam ID of the candidate beam.
 23. Themethod of claim 12, and comprising: performing a random access channel(RACH) procedure on the second component carrier, and wherein the signalto the base station corresponds to the RACH procedure on the secondcomponent carrier.
 24. An apparatus for wireless communications,comprising: a processor; and a memory storing instructions and inelectronic communication with the processor, the processor beingconfigured to execute the instructions to: establish direct wirelesscommunication with a UE over a first component carrier using one or morebeams; wirelessly receive a signal directly from the UE over a secondcomponent carrier in response to the UE initiating beam recovery;identify a candidate beam on the first component carrier based on thesignal received on the second component carrier; and wirelesslycommunicate directly with the UE over the first component carrier usingthe candidate beam.
 25. The apparatus of claim 24, wherein the signalfrom the UE comprises a beam measurement report for the first componentcarrier on resources allocated to the UE for uplink transmission on thesecond component carrier.
 26. The apparatus of claim 25, wherein: thebeam measurement report comprises at least one or more of a beam ID ofthe candidate beam or the beam ID of a current active beam.
 27. Theapparatus of claim 24, wherein the signal from the UE identifies thatthe UE has initiated beam recovery is either a beam recovery schedulingrequest (BR-SR) or a scheduling request (SR).
 28. The apparatus of claim24, wherein the processor is further configured to execute theinstructions to: transmit a request from the base station to the UE fora beam measurement report for the first component carrier in response toreceiving the BR-SR from the UE.
 29. The apparatus of claim 24, whereinthe processor is further configured to execute the instructions to:wirelessly transmit a beam switch command directly from the base stationto the UE, wherein the beam switch command instructs the UE to switchactive communication from the one or more beams to the candidate beam.30. The apparatus of claim 24, wherein the signal from the UE identifiesa beam ID of the candidate beam.
 31. The apparatus of claim 24, whereinthe processor is further configured to execute the instructions to:utilize a random access procedure on the second component carrier forbeam recovery on the first component carrier.
 32. The apparatus of claim24, wherein: the first component carrier is a MMW carrier and the secondcomponent carrier is a sub-6 GHz carrier.
 33. The apparatus of claim 24,wherein the signal from the UE corresponds to a random access channel(RACH) procedure on the second component carrier.
 34. An apparatus forwireless communications, comprising: a processor; and a memory storinginstructions and in electronic communication with the processor, theprocessor being configured to execute the instructions to: wirelesslycommunicate directly with a base station over a first component carrierusing one or more beams; determine to trigger beam recovery for thefirst component carrier; identify a candidate beam for direct wirelesscommunication with the base station based on the determining; andwirelessly transmit a signal directly from the UE to the base stationover a second component carrier to signal beam recovery for the firstcomponent carrier.
 35. The apparatus of claim 34, wherein the processoris further configured to execute the instructions to: generate a beammeasurement report regarding the first component carrier; and wirelesslytransmit the beam measurement report for the first component carrierdirectly to the base station on the second component carrier onresources allocated for uplink transmission on the second componentcarrier.
 36. The apparatus of claim 35, wherein: the beam measurementreport is generated by a MAC layer of the UE and multiplexed with uplinkdata on PUSCH of the second component carrier.
 37. The apparatus ofclaim 35, wherein: the beam measurement report comprises at least one ormore of a beam ID of the candidate beam or the beam ID of a currentactive beam.
 38. The apparatus of claim 35, wherein: the beammeasurement report comprises a beam strength measurement for thecandidate beam.
 39. The apparatus of claim 34, wherein the signal fromthe UE identifies that the UE has initiated beam recovery is either abeam recovery scheduling request (BR-SR) or a scheduling request (SR).40. The apparatus of claim 39, wherein the instructions are furtherexecutable by the processor to: monitor the first component carrier onthe one or more beams for a trigger to generate a beam measurementreport in response to transmitting the logical signal from the UE thatindicates that the UE has triggered beam recovery for the firstcomponent carrier.
 41. The apparatus of claim 34, wherein theinstructions are further executable by the processor to: receive arequest from the base station for a beam measurement report for thefirst component carrier; generate the beam measurement report regardingthe first component carrier in response to receiving the request; andwirelessly transmit the beam measurement report regarding the firstcomponent carrier directly to the base station over the second componentcarrier.
 42. The apparatus of claim 34, wherein the signal from the UEidentifies that the UE has initiated beam recovery comprises a beamrecovery scheduling request (BR-SR), and wherein the instructions arefurther executable by the processor to: monitor PDCCH on the secondcomponent carrier for DCI related to the first component carrier inresponse to transmitting the BR-SR to the base station.
 43. Theapparatus of claim 34, wherein the signal from the UE identifies thatthe UE has initiated beam recovery comprises a beam recovery schedulingrequest (BR-SR), and wherein the instructions are further executable bythe processor to: monitor the second component carrier for beam switchcommand from the base station in response to transmitting the BR-SR tothe base station, wherein the beam switch command requests the UE toswitch communication to the candidate beam.
 44. The apparatus of claim34, wherein the signal from the UE identifies that the UE has initiatedbeam recovery comprises a beam recovery scheduling request (BR-SR), andwherein the instructions are further executable by the processor to:transmit at least one or more of a beam ID of the candidate beam in theBR-SR.
 45. The apparatus of claim 34, wherein the processor is furtherconfigured to execute the instructions to: initiate a random accesschannel (RACH) procedure on the second component carrier, and whereinthe signal transmitted directly to the base station corresponds to theRACH procedure on the second component carrier.
 46. A non-transitorycomputer readable medium storing code for wireless communications, thecode comprising instructions executable by a processor of a wirelesscommunication device to: establish direct wireless communication with aUE over a first component carrier using one or more beams; wirelesslyreceive a signal directly from the UE over a second component carrier inresponse to the UE initiating beam recovery; identify a candidate beamon the first component carrier based on the signal received on thesecond component carrier; and wirelessly communicate directly with theUE over the first component carrier using the candidate beam.
 47. Anon-transitory computer readable medium storing code for wirelesscommunications, the code comprising instructions executable by aprocessor of a user equipment (UE) to: wirelessly communicate directlywith a base station over a first component carrier using one or morebeams; determine to trigger beam recovery for the first componentcarrier; identify a candidate beam for direct wireless communicationwith the base station based on the determining; and wirelessly transmita signal directly from the UE to the base station over a secondcomponent carrier to signal beam recovery for the first componentcarrier.
 48. An apparatus for wireless communications at a wirelesscommunication device, the apparatus comprising: means for establishingdirect wireless communication with a UE over a first component carrierusing one or more beams; means for wirelessly receiving a a signaldirectly from the UE over a second component carrier in response to theUE initiating beam recovery; means for identifying a candidate beam onthe first component carrier based on the BR-SR received on the secondcomponent carrier; and means for wirelessly communicating directly withthe UE over the first component carrier using the candidate beam.
 49. Anapparatus for wireless communications at a user equipment (UE), theapparatus comprising: means for wirelessly communicating directly with abase station over a first component carrier using one or more beams;means for determining to trigger beam recovery for the first componentcarrier; means for identifying a candidate beam for direct wirelesscommunication with the base station based on the determining; and meansfor wirelessly transmitting a signal directly from the UE to the basestation over a second component carrier to signal beam recovery for thefirst component carrier.